Stuart G. Poss writes:

Date: Sat, 27 Nov 1999 10:47:58 -0700 [...] Elliptical Fourier transforms [... good reference list including Kuhl and Giardina 1982]

and also

Fourier Descriptors and Their Applications in Biology by Pete E. Lestrel (Editor), Cambridge University Press, 1997.

As I recall, this has a paper using Kuhl and Giardina to identify many species of oak and maple trees algorithmically.

As a biologically naive outsider, I would have thought that there is an interesting problem of authority for statistical characters not much different from other authority questions, namely how/where/who/when were the statistical parameters estimated. My impression about Elliptical Fourer Descriptors---which I think is a neat idea---is that the literature is mostly devoted to showing that they work, and not to otherwise collecting parameter estimates.

A student of mine implemented Kuhl and Giardina in matlab and my recollection is that you can make EFD's independent of size and orientation, so sloppy scanning can do pretty well. However, fall came to New England, the semester and her interestd waned and we never tested her implementation. If I'm right that this is robust to size and orientation, then it would be a cute citizen science application. People could send their leaf images to a central server, and hordes of biology students could then quickly (or slowly) assign a species in furtherence of the parameter estimate. David Hearn is doing something like this at http://ag.arizona.edu/~dhearn/help/PlantID.html.